Safeline STANDARD SERIES, Инструкция по эксплуатации

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Page 4
A comparison can be made with a
commercial/domestic Hi-Fi system. The volume
control of the Hi-Fi increases/decreases the
amplitude of all signals just like the metal detector
sensitivity control. The bass control of the Hi-Fi
selectively controls the low frequency notes only.
This is similar to the phase discrimination circuit,
however the phase discrimination circuit in the
Safeline metal detector is very much more
selective.
Signals from the detector coil system can also be
represented as shown in Fig 2.
Fig. 2
The characteristic of the phase discrimination.
circuit is as shown in Fig. 3 and may be positioned
by changing the phase setting.
Fig. 3
Fig. 4
It can be seen from Fig. 4 that the effects of
unwanted signals may be minimised by aligning the
phase discrimination with the unwanted signal,
such as product signals. When aligned the
amplitude of unwanted signal required to trigger the
detector will be increased.
Fortunately, most products do not give a significant
product effect signal, this allows the phase
discriminator to be used for rejecting vibration
signals. The optimum setting of phase is 0000. ie
aligned to vibration this gives the maximum
rejection of vibration signals and equalised
sensitivity.
In general, if the phase discrimination is aligned to
some angle other than vibration, the detector's
sensitivity to ferrous metal will increase and the non
ferrous/stainless steel sensitivity decrease.
Vibration effects will also become more noticeable.